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I have a divider circuit similar to a x10 scope probe.

I need a bandwidth of least 100MHz, preferably greater.

I am using through-hole MICA capacitors (1%). The capacitors have a low enough ESL that they should be adequate.

While laying out the board I had a thought.

If the capacitors are placed parallel to each other the B field should cancel out, making the inductance effectively zero (or closer to zero.)

This should improve the bandwidth of the divider circuit, right?

There is a resistor divider and a variable glass cap not show in the circuit below, but the basic idea is that in the RIGHT circuit any B field in 1 capacitor will induce an equal and opposite current in the second capacitor.

Am I right? Is this a technique for expanding the range of capacitors?

enter image description here

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Simulation results confirm my assumption. However, I would still like to know if this is an actual technique used to extend performance.

With the capacitors magnetically coupled the performance is better according to LTspice. This is assuming the caps have the same ESL and are perfectly coupled.

  • The input impedance has Zero inductance.
  • The output of the divider is more stable around the cap's resonant frequency.

The 1st plot compares the input impedance of the divider (Zin).

The 2nd plot compares the divider output voltage (Vout/Vin).

  • Green: coupled
  • Purple: not-coupled

enter image description here

enter image description here

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    \$\begingroup\$ Simulators can only show you theoretical results from the assumptions you feed it. You have to set the coupling between the components when you set them up in LTspice. Whether that assumed coupling even remotely resembles reality is another question, and one that can only be answered by a really detailed analysis or by building the circuit for real. It would surprise the stuffing out of me if reality matches your simulation. \$\endgroup\$
    – JRE
    Feb 15, 2022 at 14:15

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